New Legionnaires test 'in hours'

By Dr David Gregory
BBC Science correspondent, West Midlands

The new test has made the rapid-response lab possible

A West Midlands scientific company says it has invented a new test which cuts the time to identify Legionnaires disease from weeks to just hours.

It is a discovery that could save money and, more importantly, lives.

The firm has found a new way of detecting legionella pnuemophila bacteria and as a result says it has created Britain's first rapid-response lab for detecting Legionnaires' disease.

It looks just like a brand new ambulance, complete with flashing lights, but this is a very special vehicle.

The new test was the idea of Jonathan Usher from Mercian Science, based in Minworth.

Legionnaires disease About 350 people contract Legionnaires disease every year in the UK People are infected when sprayed with a fine mist of infected water The very young and the elderly are most at risk, in particular older men who are also smokers Symptoms are similar to pneumonia and in about 5% of cases the disease is fatal Survivors are often left with long term health problems

He said the existing testing method has drawbacks.

"First you filter the bacteria from a litre water sample and then you culture them on agar," he said.

"That typically takes 10 days and you don't know if the system is clear or if you have problems."

As a result a hospital with suspected contamination has to wait 10 days to actually confirm an outbreak then another 10 days after cleaning to make sure the disinfecting process has been effective.

In that time the hospital may have to stay closed.

Mr Usher said the new test still uses a water sample but can be completed in about four hours because it no longer needs to grow a bacteria.

Instead a stain is used which will only stain the organism needed to be identified to confirm an outbreak.

"Once stained you put your slide under a microscope and turn on an ultraviolet light," he said.

"The legionella bacteria glow an eerie apple green, and in the laboratory it's possible to pick out single bacteria, giving a very accurate count of the level of contamination in the water sample."